http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.crypto.signers;

import java.io.IOException;
import java.math.BigInteger;


An interface for different encoding formats for DSA signatures.

/**
 * An interface for different encoding formats for DSA signatures.
 */
public interface DSAEncoding
{
    
Decode the (r, s) pair of a DSA signature.

Params:
  • n – the order of the group that r, s belong to.
  • encoding – an encoding of the (r, s) pair of a DSA signature.
Throws:
Returns:the (r, s) of a DSA signature, stored in an array of exactly two elements, r followed by s.
/**
     * Decode the (r, s) pair of a DSA signature.
     * 
     * @param n the order of the group that r, s belong to.
     * @param encoding an encoding of the (r, s) pair of a DSA signature.
     * @return the (r, s) of a DSA signature, stored in an array of exactly two elements, r followed by s.
     * @throws IOException
     */
    BigInteger[] decode(BigInteger n, byte[] encoding) throws IOException;

    
Encode the (r, s) pair of a DSA signature.

Params:
  • n – the order of the group that r, s belong to.
  • r – the r value of a DSA signature.
  • s – the s value of a DSA signature.
Throws:
Returns:an encoding of the DSA signature given by the provided (r, s) pair.
/**
     * Encode the (r, s) pair of a DSA signature.
     * 
     * @param n the order of the group that r, s belong to.
     * @param r the r value of a DSA signature.
     * @param s the s value of a DSA signature.
     * @return an encoding of the DSA signature given by the provided (r, s) pair.
     * @throws IOException
     */
    byte[] encode(BigInteger n, BigInteger r, BigInteger s) throws IOException;
}